Bifurcated sliding seal

ABSTRACT

The present disclosure relates generally to a sliding seal between two components. The sliding seal includes a first seal section and an uncoupled second seal section which allows the first and second seal sections to move relative to one another during relative movement between the two components. A wave spring and/or a rope seal is disposed between the first and second seal sections biases the first and second seal sections away from one another.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.14/830,768 filed on Aug. 20, 2015, which claims the benefit of andincorporates by reference herein the disclosure of U.S. Ser. No.62/068,496, filed on Oct. 24, 2014, the contents each of which areincorporated herein by reference thereto.

TECHNICAL FIELD OF THE DISCLOSURE

The present disclosure is generally related to seals and, morespecifically, to a sliding seal.

BACKGROUND OF THE DISCLOSURE

Seals are used in many applications to prevent or limit the flow of agas or liquid from one side of the seal to another side of the seal. Forexample, seals are used in many areas within a gas turbine engine toseal the gas path of the engine. The performance of gas path sealsaffects engine component efficiency. For example, the loss of secondaryflow into the gas path of a turbine engine has a negative effect onengine fuel burn, performance/efficiency, and component life. A metalw-seal or a non-metallic rope seal are typical seals used to seal orlimit secondary flow between segmented or full-hoop turbine components.However, exposure to significant relative deflections between adjacentcomponents and/or elevated temperatures can preclude the use of thesetypes of seals or cause them to fail prematurely. If subjected tosignificant deflections, a w-seal will deform and become ineffective.Using a higher strength material improves deflection capabilitysomewhat, but generally at the expense of limiting temperaturecapability. Wear resistance can be a problem as well in an environmentof significant relative motion. A rope seal typically has hightemperature capability but has even less flexibility.

Improvements in seal design are therefore needed in the art.

SUMMARY OF THE DISCLOSURE

In one embodiment, a seal for sealing a space defined by first andsecond adjacent components disposed about a centerline is disclosed, theseal comprising: a first seal section; and a second seal section;wherein the first and second seal sections are configured to sealinglyengage with the first and second components; a wave spring disposedbetween the first and second seal sections and operative to bias thefirst seal section and the second seal section away from one another;and wherein the first and second seal sections are configured to moverelative to one another.

In a further embodiment of the above, the first seal section includes afirst base and a first leg extending from the first base; and the secondseal section includes a second base and a second leg extending from thesecond base.

In a further embodiment of any of the above, the first seal section andthe second seal section are substantially L-shaped in cross-section.

In a further embodiment of any of the above, the first base and thesecond base are oriented substantially axially; and the first leg andthe second leg are oriented substantially radially.

In a further embodiment of any of the above, the first base is supportedby the second base.

In a further embodiment of any of the above, the seal is formed from amaterial selected from one of a high-temperature metal alloy, ahigh-temperature ceramic fiber material, and a high-temperature ceramicfiber composite, or a combination of two or more of a high-temperaturemetal alloy, a high-temperature ceramic fiber material and ahigh-temperature ceramic fiber composite.

In a further embodiment of any of the above, a coating is applied to atleast a portion of each of the first and second seal sections.

In a further embodiment of any of the above, a sheath is providedcovering at least a portion of each of the first and second sealsections.

In a further embodiment of any of the above, the first and second sealsections are substantially annular.

In a further embodiment of any of the above, the first and second sealsections respectively define first and second gaps at respective opposedends thereof.

In a further embodiment of any of the above, a bridging seal is disposedadjacent the first and second seal sections and at least partiallycovering the first and second gaps.

the first seal section comprises a first substantially rounded end incontact with the first component along a first single circumferentialline of contact; and the second seal section comprises a secondsubstantially rounded end in contact with the second component along asecond single circumferential line of contact.

In a further embodiment of any of the above, the first seal sectioncomprises a third substantially rounded end in contact with the secondseal section along a third single circumferential line of contact; andthe second seal section comprises a fourth substantially rounded end incontact with the second component along a fourth single circumferentialline of contact.

In a further embodiment of any of the above, the wave spring biases thefirst seal section and the second seal section away from one another inan axial direction.

In a further embodiment of any of the above, a plurality of tabs areprovided extending from the first seal section and/or the second sealsection and wrapping over a radially outer edge of the wave spring.

In a further embodiment of any of the above, a first compliant seal isdisposed between the first seal section and the first component; and asecond compliant seal is disposed between the second seal section andthe first component.

In another embodiment, a system is disclosed, comprising: a firstcomponent including a first surface; a second component including asecond surface, the second component disposed adjacent the firstcomponent and defining a seal cavity therebetween; wherein the first andsecond components are disposed about an axial centerline; and a sealdisposed in the seal cavity, the seal including: a first seal section;and a second seal section; a wave spring disposed between the first andsecond seal sections and operative to bias the first seal section andthe second seal section away from one another; and wherein the first andsecond seal sections are configured to move relative to one another;wherein pressure within the seal cavity urges the seal to seat againstthe first surface and the second surface.

In a further embodiment of any of the above, the first seal sectionincludes a first base and a first leg extending from the first base; andthe second seal section includes a second base and a second legextending from the second base.

In a further embodiment of any of the above, the first seal sectioncomprises a first substantially rounded end in contact with the firstcomponent along a first single circumferential line of contact; thesecond seal section comprises a second substantially rounded end incontact with the second component along a second single circumferentialline of contact; the first seal section comprises a third substantiallyrounded end in contact with the second seal section along a third singlecircumferential line of contact; and the second seal section comprises afourth substantially rounded end in contact with the second componentalong a fourth single circumferential line of contact.

In another embodiment, a seal for sealing a space defined by first andsecond adjacent components disposed about a centerline is disclosed, theseal comprising: a first seal section including a first base, a firstleg and a frustoconical section joining the first base and the firstleg; and a second seal section including a second base and a second legextending from the second base; wherein the first and second sealsections are configured to sealingly engage with the first and secondcomponents; a rope seal disposed between the first and second sealsections and operative to bias the first seal section and the secondseal section away from one another; and wherein the first and secondseal sections are configured to move relative to one another.

Other embodiments are also disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments and other features, advantages and disclosures containedherein, and the manner of attaining them, will become apparent and thepresent disclosure will be better understood by reference to thefollowing description of various exemplary embodiments of the presentdisclosure taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic cross-sectional view of a gas turbine engine.

FIG. 2 is a schematic cross-sectional view of a seal and seal cavity inan embodiment.

FIG. 3 is a schematic cross-sectional view of a seal and seal cavity inan embodiment.

FIG. 4 is a schematic plan view of a wave spring in an embodiment.

FIG. 5 is a schematic cross-sectional view of a seal and seal cavity inan embodiment.

FIG. 6 is a schematic cross-sectional view of a seal and seal cavity inan embodiment.

FIG. 7 is a schematic cross-sectional view of a seal and seal cavity inan embodiment.

FIG. 8 is a schematic cross-sectional view of a seal and seal cavity inan embodiment.

DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENTS

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to certain embodiments andspecific language will be used to describe the same. It willnevertheless be understood that no limitation of the scope of theinvention is thereby intended, and alterations and modifications in theillustrated device, and further applications of the principles of theinvention as illustrated therein are herein contemplated as wouldnormally occur to one skilled in the art to which the invention relates.

FIG. 1 schematically illustrates a gas turbine engine 20. The gasturbine engine 20 is disclosed herein as a two-spool turbofan thatgenerally incorporates a fan section 22, a compressor section 24, acombustor section 26 and a turbine section 28. Alternative engines mightinclude an augmentor section (not shown) among other systems orfeatures. The fan section 22 drives air along a bypass flow path B in abypass duct, while the compressor section 24 drives air along a coreflow path C for compression and communication into the combustor section26 then expansion through the turbine section 28. Although depicted as atwo-spool turbofan gas turbine engine in the disclosed non-limitingembodiment, it should be understood that the concepts described hereinare not limited to use with two-spool turbofans as the teachings may beapplied to other types of turbine engines including three-spoolarchitectures.

The exemplary engine 20 generally includes a low speed spool 30 and ahigh speed spool 32 mounted for rotation about an engine centrallongitudinal axis A relative to an engine static structure 36 viaseveral bearing systems 38. It should be understood that various bearingsystems 38 at various locations may alternatively or additionally beprovided, and the location of bearing systems 38 may be varied asappropriate to the application.

The low speed spool 30 generally includes an inner shaft 40 thatinterconnects a fan 42, a low pressure compressor 44 and a low pressureturbine 46. The inner shaft 40 is connected to the fan 42 through aspeed change mechanism, which in exemplary gas turbine engine 20 isillustrated as a geared architecture 48 to drive the fan 42 at a lowerspeed than the low speed spool 30. The high speed spool 32 includes anouter shaft 50 that interconnects a high pressure compressor 52 and highpressure turbine 54. A combustor 56 is arranged in exemplary gas turbine20 between the high pressure compressor 52 and the high pressure turbine54. An engine static structure 36 is arranged generally between the highpressure turbine 54 and the low pressure turbine 46. The engine staticstructure 36 further supports bearing systems 38 in the turbine section28. The inner shaft 40 and the outer shaft 50 are concentric and rotatevia bearing systems 38 about the engine central longitudinal axis Awhich is collinear with their longitudinal axes.

The core airflow is compressed by the low pressure compressor 44 thenthe high pressure compressor 52, mixed and burned with fuel in thecombustor 56, then expanded over the high pressure turbine 54 and lowpressure turbine 46. The turbines 46, 54 rotationally drive therespective low speed spool 30 and high speed spool 32 in response to theexpansion. It will be appreciated that each of the positions of the fansection 22, compressor section 24, combustor section 26, turbine section28, and fan drive gear system 48 may be varied. For example, gear system48 may be located aft of combustor section 26 or even aft of turbinesection 28, and fan section 22 may be positioned forward or aft of thelocation of gear system 48.

The engine 20 in one example is a high-bypass geared aircraft engine. Ina further example, the engine 20 bypass ratio is greater than about six(6), with an example embodiment being greater than about ten (10), thegeared architecture 48 is an epicyclic gear train, such as a planetarygear system or other gear system, with a gear reduction ratio of greaterthan about 2.3 and the low pressure turbine 46 has a pressure ratio thatis greater than about five. In one disclosed embodiment, the engine 20bypass ratio is greater than about ten (10:1), the fan diameter issignificantly larger than that of the low pressure compressor 44, andthe low pressure turbine 46 has a pressure ratio that is greater thanabout five 5:1. Low pressure turbine 46 pressure ratio is pressuremeasured prior to inlet of low pressure turbine 46 as related to thepressure at the outlet of the low pressure turbine 46 prior to anexhaust nozzle. The geared architecture 48 may be an epicycle geartrain, such as a planetary gear system or other gear system, with a gearreduction ratio of greater than about 2.3:1. It should be understood,however, that the above parameters are only exemplary of one embodimentof a geared architecture engine and that the present invention isapplicable to other gas turbine engines including direct driveturbofans.

A significant amount of thrust is provided by the bypass flow B due tothe high bypass ratio. The fan section 22 of the engine 20 is designedfor a particular flight condition—typically cruise at about 0.8 Mach andabout 35,000 feet (10,688 meters). The flight condition of 0.8 Mach and35,000 ft (10,688 meters), with the engine at its best fuelconsumption—also known as “bucket cruise Thrust Specific FuelConsumption (‘TSFC’)”—is the industry standard parameter of lbm of fuelbeing burned divided by lbf of thrust the engine produces at thatminimum point. “Low fan pressure ratio” is the pressure ratio across thefan blade alone, without a Fan Exit Guide Vane (“FEGV”) system. The lowfan pressure ratio as disclosed herein according to one non-limitingembodiment is less than about 1.45. “Low corrected fan tip speed” is theactual fan tip speed in ft/sec divided by an industry standardtemperature correction of [(Tram ° R)/(518.7° R)]^(0.5). The “Lowcorrected fan tip speed” as disclosed herein according to onenon-limiting embodiment is less than about 1150 ft/second (350.5 m/sec).

FIG. 2 schematically illustrates a cross-sectional view of a seal cavity100 formed by two axially-adjacent segmented or full-hoop turbinecomponents 102 and 104 which may move axially, radially, andcircumferentially relative to one another about an axial centerline ofthe turbine engine. It will be appreciated that although turbinecomponents are used to demonstrate the positioning and functioning ofthe seals disclosed herein, this is done by way of illustration only andthe seals disclosed herein may be used in other applications. A nominaldesign clearance 106 exists between the components 102 and 104. Withinthe seal cavity 100 lies a w-seal 108 formed from a material appropriateto the anticipated operating conditions (e.g., deflection, temperaturechange, pressure, etc.) of the w-seal 108, such a nickel-base alloy toname just one non-limiting example.

The design and material used in the construction of the w-seal 108causes it to be deflected both forward and aft within the cavity 100,thereby causing it to seat against the components 102 and 104, even whenthe components 102 and 104 move relative to each other causing theclearance 106 to change. However, if subjected to significantdeflections and/or temperature, a w-seal 108 may deform, causing it tobecome ineffective and potentially liberate.

FIG. 3 schematically illustrates a cross-sectional view of a seal cavity200 formed by two axially-adjacent segmented or full hoop turbinecomponents 202 and 204 which may move axially, radially, andcircumferentially relative to one another about an axial centerline ofthe turbine engine. A nominal design clearance 206 exists between thecomponents 202 and 204. Component 202 includes a surface 210 facing theseal cavity 200 and component 204 includes surfaces 208 and 211 facingthe seal cavity 200. Within the seal cavity 200 lies a seal 212 formedfrom a material appropriate to the anticipated operating conditions ofthe seal 212, such as a high-temperature metal alloy, a high temperatureceramic material, a high temperature ceramic composite, or a combinationof two or more of these, to name just a few non-limiting examples. Theseal 212 is formed from a first seal section 214 and a second sealsection 216. The first seal section 214 is generally L-shaped incross-section and includes a base 218 and a leg 220. The second sealsection 216 is also generally L-shaped in cross-section and includes abase 222 and a leg 224. The bases 218, 222 are oriented substantiallyaxially, while the legs 220, 224 are oriented substantially radially.The base 218 is supported by the base 222 in an embodiment, while inanother embodiment the base 222 is supported by the base 218. The seal212 may include a coating and/or a sheath to provide increased wearresistance.

The seal section 214 includes a forward substantially rounded end 226 incontact with the surface 208 such that the seal section 214 contacts thesurface 208 along a single circumferential line of contact. As usedherein, the phrase “circumferential line of contact” is intended toencompass lines that form a complete circle but which may have a gapformed therein, and includes lines with a nominal radial or axialthickness. The seal section 214 also includes an aft substantiallyrounded end 228 in contact with the seal section 216 (or the surface 211in some embodiments) such that the seal section 214 contacts the sealsection 216 (or the surface 211 in some embodiments) along a singlecircumferential line of contact. The seal section 216 includes an aftsubstantially rounded end 230 in contact with the surface 210 such thatthe seal section 216 contacts the surface 210 along a singlecircumferential line of contact. The seal section 216 also includesforward substantially rounded end 232 in contact with the surface 211(or the seal section 214 in some embodiments) such that the seal section216 contacts the surface 211 (or the seal section 214 in someembodiments) along a single circumferential line of contact.

A full hoop wave spring 234 is disposed within the cavity defined by theseal section 214 and the seal section 216. A plan view of a portion ofthe wave spring 234 is illustrated in FIG. 4. In an embodiment, one (seeFIG. 3) or both (see FIG. 5) of the seal sections 214, 216 may include aplurality of tabs 236 spaced around their radially outer circumference.The tabs 236 wrap over the radially outer edge of the wave spring 234,thereby securing the wave spring 234 within the cavity defined by theseal section 214 and the seal section 216. When both the seal section214 and the seal section 216 include tabs 236, the seal 212 comprises adiscrete assembly that may be handled and installed as a single piece.

Pressure in a secondary flow cavity 238 is transmitted to the sealcavity 200 through an opening defined by the components 202, 204. Thispressure acts upon the surfaces of the seal sections 214, 216, therebycausing the leg 220 to seat against the surface 208 of the component204, the leg 224 to seat against the surface 210 of the component 202,and the base 218 to seat against the base 222. The load applied by base218 to base 222 helps base 222 to seat against the surface 211, therebyproviding a secondary seal against flow that may leak past the leg220/surface 208 interface, such as during engine start-up, for example.This prevents most or all of the secondary flow cavity 238 gases fromreaching the design clearance 206 area and flow path. As the twocomponents 202 and 204 move relative to each other in the axial and/orradial direction, the seal sections 214, 216 are free to slide relativeto one another in the axial and circumferential directions while thepressure forces acting upon the surfaces of the seal sections 214, 216load the seal 212 so that it remains in contact with both components 202and 204 as shown. Therefore, sealing is maintained while the components202 and 204 and the components of the seal 212 move relative to oneanother. Because the seal sections 214, 216 slide with respect to oneanother and with respect to the components 202, 204, the seal 212 is notsubstantially deflected by the relative movement between the components202 and 204.

Furthermore, the circumferentially-oriented wave spring 234 pushes theseal sections 214 to remain in contact with the forward wall 208, andalso pushes the seal section 216 to remain in contact with the aft wall210 when the cavity 200 is not pressurized. This prevents the seal 212from being damaged during transportation and installation, and alsoensures that the seal 212 is instantly and positivelypressurized/pressure-energized at engine start-up. In operation, thepressure loading on both seal sections 214, 216 is significant, becausethe contact points 226, 230 are well outboard, ensuring good sealing atthe contact points 226, 230. Seal section 214 is split at onecircumferential location to enable pressure to load the seal section 214radially inward against the seal section 216. Also, splitting the sealsection 216 creates an additional sealing surface at the bottom of theseal cavity 200, as well as allowing the seal 212 to be packaged withina smaller radial design space. Leakage can be reduced significantly atthe split location of each seal section 214, 216 by off-setting onesplit relative to the other, and further reduced by adding a slidingbridge to the cover the gap in the radially outer seal section 214and/or the outer portion of section 216.

In the embodiment of FIG. 5, the seal 212 may include a full hoophigh-temperature and compliant seal 240, such as a woven or braidedceramic rope seal or flat fabric (for example, NEXTEL ceramic textileavailable from The 3M Company of Maplewood, Minn. USA, to name just onenon-limiting example) to partially seal stair-stepped gaps typical ofsegmented part interfaces of the components 202, 204 in someembodiments. The compliant seal 240 may be disposed between the leg 220and the surface 208 of the component 204, as well as between the leg 224and the surface 210 of the component 202. The compliant seal 240 may bebonded to or mechanically attached to the seal section 214, 216 or tothe component 202, 204. The compliant seal 240 adds compliance to theseal 212 in the axial direction. In another embodiment, anothercompliant seal (not shown) may also be added to the radially inner sideof leg 222 to contact surface 211 (or to the radially inner side of leg218 in embodiments where leg 222 is supported by leg 218).

In the embodiment of FIG. 6, the wave spring may be replaced with a ropeseal 250. An angled portion 252, extending both radially and axially,may be provided to couple the base 218 to the leg 220 and to provide amain surface upon which the rope seal 250 my act with respect to theseal section 214. The angled portion 252 provides forward space intowhich the rope seal 250 may move when compressed, thereby increasingaxial resilience. A radially outer extension 254 provides radial spaceinto which the rope seal 250 may move when compressed, therebyincreasing radial resilience. The extension 254 additionally traps therope seal 250 between the seal sections 214, 216 to prevent liberationof the rope seal 250. Although the rope seal 250 may be less resilientthan a wave spring in some embodiments, the rope seal 250 providesadditional sealing for flow between the seal sections 214, 216 and mayalso enable use of the seal 212 in higher temperature environments. Forseal applications with only moderate axial travel, the rope seal 250will provide adequate resilience to ensure that the seal sections 214,216 are in contact with the components 202, 204 during engine start.During engine operation, pressure differential alone provides the forcerequired to ensure that the seal sections 214, 216 are in contact withthe components 202, 204.

In the embodiment of FIG. 7, the seal of FIG. 6 may include a full hoophigh-temperature and compliant seal 240, such as a woven or braidedceramic rope seal or flat fabric (for example, NEXTEL ceramic textileavailable from The 3M Company of Maplewood, Minn. USA, to name just onenon-limiting example) to partially seal stair-stepped gaps typical ofsegmented part interfaces of the components 202, 204 in someembodiments. The compliant seal 240 may be disposed between the leg 220and the surface 208 of the component 204, as well as between the leg 224and the surface 210 of the component 202. The compliant seal 240 may bebonded to or mechanically attached to the seal section 214, 216 or tothe component 202, 204. The compliant seal 240 adds compliance to theseal 212 in the axial direction. In another embodiment, anothercompliant seal (not shown) may also be added to the radially inner sideof leg 222 to contact surface 211.

In the embodiment of FIG. 8, seal section 214 is substantially U-shapedin cross-section and defines a cavity 260 therein. A rope seal 262 isdisposed within the cavity 260 and sealingly engages an outer radialsurface 209 of the component 204. A first wave spring 234 a is disposedbetween the first seal section 214 and the second seal section 216 andis operative to bias the first seal section 214 away from the secondseal section 216 in the radial direction. This causes the rope seal 262to seal against the surface 209 of the component 204, while theprotrusion 232 of the second seal section 216 seals against the surface211 of the component 204. An optional second wave spring 234 b isdisposed between the component 204 and both the first seal section 214and the second seal section 216 The second seal section 216 may includea radial extension 264 of the base 222 that is contacted by the secondwave spring 234 b. The axial bias applied by the second wave spring 234b against the seal sections 214, 216 biases the protrusion 230 tosealingly engage the surface 210 of the component 202. The substantiallyU-shaped seal section 214 traps the rope seal 262 between the sealsection 214 and the surface 209 of the component 204 to preventliberation of the rope seal 262. The wave spring 234 a providesresilience in the radial direction, while the wave spring 234 b providesresilience in the axial direction. The wave springs 234 a, 234 b ensurethat the seal sections 214, 216 are in contact with the components 202,204 during engine start. During operation of the engine, thedifferential pressure acting on the seal 212 creates an axial load atthe protrusion 230 without requiring axial loading from the second wavespring 234 b.

Compared to the seal 108 of FIG. 2, the wave spring 234 exhibitsimproved resilience since the wave spring 234 can be configured to havea much lower spring rate within the same axial design space. The sealsections 214, 216 are not deflected as the components 202 and 204 moverelative to each other during engine assembly and engine operation,which is beneficial because the seal sections 214, 216 can be made froma lower strength and/or thicker sheet material that may be lower cost,have higher temperature capability, be more manufacturable, morewear-resistant, and/or more wear tolerant. Furthermore, the wave spring234 is shielded from high conductive and radiant heat load by the sealsections 214, 216. Additionally, the seal 212 is less susceptible todistortion or breakage, which can cause leakage of gas past the seal 212and/or liberation of the seal.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly certain embodiments have been shown and described and that allchanges and modifications that come within the spirit of the inventionare desired to be protected.

What is claimed is:
 1. A seal for sealing a space defined by first andsecond adjacent components disposed about a centerline, the sealcomprising: a first seal section including a first base, a first leg anda frustoconical section joining the first base and the first leg; and asecond seal section including a second base and a second leg extendingfrom the second base; wherein the first and second seal sections areconfigured to sealingly engage with the first and second components; arope seal disposed between the first and second seal sections andoperative to bias the first seal section and the second seal sectionaway from one another; and wherein the first and second seal sectionsare configured to move relative to one another.
 2. The seal of claim 1,wherein the first base is supported by the second base.
 3. The seal ofclaim 1, wherein the seal is formed from a material selected from one ofa high-temperature metal alloy, a high-temperature ceramic fibermaterial, and a high-temperature ceramic fiber composite, or acombination of two or more of a high-temperature metal alloy, ahigh-temperature ceramic fiber material and a high-temperature ceramicfiber composite.
 4. The seal of claim 1, further comprising: a coatingapplied to at least a portion of each of the first and second sealsections.
 5. The seal of claim 1, further comprising: a sheath coveringat least a portion of each of the first and second seal sections.
 6. Theseal of claim 1, wherein: the first and second seal sections aresubstantially annular.
 7. The seal of claim 6, wherein the first andsecond seal sections respectively define first and second gaps atrespective opposed ends thereof.
 8. The seal of claim 7, furthercomprising a bridging seal disposed adjacent the first and second sealsections and at least partially covering the first and second gaps. 9.The seal of claim 1, wherein: the first seal section comprises a firstsubstantially rounded end in contact with the first component along afirst single circumferential line of contact; and the second sealsection comprises a second substantially rounded end in contact with thesecond component along a second single circumferential line of contact.10. The seal of claim 9, wherein: the first seal section comprises athird substantially rounded end in contact with the second seal sectionalong a third single circumferential line of contact; and the secondseal section comprises a fourth substantially rounded end in contactwith the second component along a fourth single circumferential line ofcontact.
 11. The seal of claim 1, wherein the wave spring biases thefirst seal section and the second seal section away from one another inan axial direction.
 12. The seal of claim 1, further comprising aplurality of tabs extending from the first seal section and/or thesecond seal section and wrapping over a radially outer edge of the wavespring.
 13. The seal of claim 1, further comprising: a first compliantseal disposed between the first seal section and the first component;and a second compliant seal disposed between the second seal section andthe first component.
 14. A system, comprising: a first componentincluding a first surface; a second component including a secondsurface, the second component disposed adjacent the first component anddefining a seal cavity therebetween; wherein the first and secondcomponents are disposed about an axial centerline; and a seal disposedin the seal cavity, the seal including: a first seal section including afirst base, a first leg and a frustoconical section joining the firstbase and the first leg; and a second seal section including a secondbase and a second leg extending from the second base; wherein the firstand second seal sections are configured to sealingly engage with thefirst and second components; a rope seal disposed between the first andsecond seal sections and operative to bias the first seal section andthe second seal section away from one another; and wherein the first andsecond seal sections are configured to move relative to one another; andwherein pressure within the seal cavity urges the seal to seat againstthe first surface and the second surface.
 15. The system of claim 14,wherein: the first seal section comprises a first substantially roundedend in contact with the first component along a first singlecircumferential line of contact; the second seal section comprises asecond substantially rounded end in contact with the second componentalong a second single circumferential line of contact; the first sealsection comprises a third substantially rounded end in contact with thesecond seal section along a third single circumferential line ofcontact; and the second seal section comprises a fourth substantiallyrounded end in contact with the second component along a fourth singlecircumferential line of contact.